Environmental cues previously paired with drug use significantly enhance drug-seeking behavior. In fact, presentation of such cues promotes relapse, even after long periods of abstinence. One potential treatment for addiction is to reduce the behavioral control of drug-associated cues. This requires understanding the nature of associations between environmental stimuli and drug reward; however, very little is known regarding how such associations are formed. The nucleus accumbens is critically involved in drug addiction, as it is known to mediate the reinforcing actions of abused drugs. It is known that modulation of drug seeking by environmental cues is mediated through the nucleus accumbens. I therefore propose to study neural alterations within the nucleus accumbens during the formation and expression of drug associations. I will first use multi-unit array electrophysiology to assess changes in neuronal activity while an initially neutral cue is paired with intravenous cocaine administration. I will then use fast-scan cyclic voltammetry to assess real time dopamine release during such associations. Results from these studies may promote treatments aimed at reducing the ability of environmental cues to enhance drug seeking. [unreadable] [unreadable] [unreadable]